Crystalline butene-1 polymers are known in the art and have a desirable combination of physical properties. For certain applications, it would be desirable to be able to plasticize crystalline butene-1 polymers to modify the polymers' hand, hardness, and tensile properties. As is known, however, it is extremely difficult to plasticize crystalline polymers and no compatible plasticized butene-1 polymer compositions are reported in the art.